The motor cortex and basal ganglia play an important role in the regulation of behavior. Clinical and experimental observations on disease or damage to the motor cortex and basal ganglia have described, among other deficits, marked impairments in the initiation of movement, in walking and in the ability to program sequences of movements. Recent electrophysiological studies by the applicant have revealed a topographic axio-distal distribution of motor cortex outputs to the caudate nucleus. Current studies suggest that this axio-distal sorting is mirrored at the level of the caudate output to the pallidum and the pallidal output to the thalamus. Our recent electrophysiological and anatomical findings have revealed that the pallidal and axial motor cortical outputs to the tegmentum may terminate within the boundaries of the Mesencephalic Locomotor Region (MLR). The proposed studies will attempt to determine the distribution of these projections, as well as the extent of the downstream projections of the MLR. These experiments should lead to a better understanding of the role of the basal ganglia in walking and in complex motor strategies requiring whole-body movements. The clinical implications of these studies are extremely significant and will hopefully suggest new procedures for alleviating the disorders produced by disease or damage to these brain systems.